Ok, so I will put the new stuff in a comment to ImagingComponents along with some note.
After the new Lazarus release new stuff will be set as compiled code and old will be put in comment
with note (so someone still using older Laz could find what to do to get it working).

Hmm, not that I know of. Probably the best way would be to just attach the patch and a note (readme or something) to svn. After Lazarus 0.9.23 is released, it can be merged (I guess there is no reason for downward compatibility then).
On the other hand ... someone who uses the Imaging Lib from svn, probably also uses Lazarus from svn (or at least he has the necessary skills to do so ;)).

Thanks for the patch. I'll update the source in SVN. Do you happen to know if there is a way to detect Lazarus version during compile time? So that it won't break for people using older Lazarus (it would use old RawImage interface).

In the lazarus revision 11861, the RawImage implementation got changed to a more OO approach, breaking the current implementation of the ImagingComponents.

I attached a patch to resolve this.